Improve custom Renovate presets and pinning

[robo9k]

Seems like existing config is not working as intended

rust-magic-sys/.github/workflows/conventional-commits.yml

Lines 28 to 29 in a0ba329

	# renovate: taiki-e/install-action
	tool: cocogitto@6.0.0

https://crates.io/crates/cocogitto/versions

---

The version of release-plz is pinned within its action

rust-magic-sys/.github/workflows/release-plz.yml

Line 49 in a0ba329

version: "0.3.139"

But this uses a different format which is not compatible with the taiki-e/install-action regex
Since the action itself is pinning its binary, there's likely no need to pin it in our workflow